It is known to provide a data acquisition system which includes a plurality of networked data acquisition units, each data acquisition unit being connected to at least one sensor and being arranged to gather survey data from the sensors. The received survey data is passed via the network to a central computing device for processing. Synchronisation of the received survey data is also carried out via the network.
However, a disadvantage of this arrangement is that the gathered survey data often includes a significant amount of noise which can be of sufficiently large magnitude to obscure the desired signal response associated with a relatively deeply buried target.
In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word “comprise” or variations such as “comprises” or “comprising” is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.